CVE-2026-77246 — MCP Atlassian: MCP HTTP Client Server-Local File Exfiltration via Unvalidated Attachment Upload Path
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false acce…
Published: 2026-09-22 · CVSS: 7.4 · CVSS 3.1
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker hostname or one allowed by MCP_ALLOWED_URL_DOMAINS. A caller can then invoke confluence_upload_attachment or the Jira attachment variant in src/mcp_atlassian/jira/attachments.py with a server-local file_path and cause the MCP process to send the file to the selected attachment endpoint. This issue is fixed in version 0.22.0.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7